Name: ______________

Hours Studied: _______

Geography 123: Weather & Climate

Exam III: April 13, 2000

Part I: Multiple-multiple Choice. Please circle the letter of every correct choice, and remember that there may be one, two, three, or four correct choices per question. Two points each.

1. Along a warm front

a. cP air is on the ground north of the front (in North America).

b. mT air is on the ground north of the front.

c. Q clouds commonly form north of the front.

d. air rises, warming as it does and therefore decreasing relative humidity.

2. The Barneveld tornado was more traumatic than the Oakfield tornado because

a. people in Barneveld knew it was coming and panicked.

b. everyone in Barneveld was affected by deaths, injuries, or property loss – or knew folks who were affected.

c. three times as many injuries occurred in Barneveld as in Oakfield.

d. the Oakfield tornado destroyed more property than did the Barneveld tornado.

3. In a thunderstorm,

a. hail is produced when raindrops freeze into pellets as they fall in downdrafts.

b. electrons accumulate at the top of the cloud.

c. the anvil is created by strong upper level winds including the jet stream, pulling the cloud top downwind.

d. a thunderbolt causes lightning.

4. Blizzards

a. are common in Wisconsin.

b. are associated with a very steep horizontal pressure gradient force.

c. are common in the northern Great Plains.

d. are usually accompanied by whiteouts.

5. Ice storms in Wisconsin

a. occur more often in March than in January.

b. are associated with cold fronts.

c. are associated with a very steep vertical pressure gradient.

d. usually last about two to three hours.

6. In a hurricane

a. the vertical pressure gradient force is minimal to nonexistent.

b. SWY energy from low latitudes is transformed and causes a very steep pressure gradient force when the latent heat of evaporation is released in the wall cloud during condensation of water vapor.

c. the dangers from precipitation are negligible because most damage is caused by the storm surge.

d. it is likely Wisconsin residents are in danger because of hurricanes moving on land from Lake Michigan.

7. A nimbostratus cloud

a. has a relative humidity of less than 100%.

b. is most often created by air rising along a cold front.

c. produces precipitation.

d. is often associated with tornado formation.

8. An mP air mass

a. is spawned over North Carolina.

b. has a higher specific humidity than an mT air mass.

c. does not affect Wisconsin.

d. is less stable in winter than a cP air mass.

9. Lightning

a. is caused by electrons flowing toward protons and completing an electrical circuit.

b. causes thunder by rapidly heating the air, causing it to expand and collide violently with adjacent air molecules.

c. kills more people on an annual basis than tornadoes in the US.

d. produces stroke-like injuries in its victims that survive.

Part II: Definitions. Please place the value or concept defined in the space provided. Two points each.

1 ______________________ An air mass characterized by high temperatures, low relative humidity, and low stability in summer.

2 ______________________ A very strong Q cloud often characterized by extreme updrafts and downdrafts and, often, by tornadoes; found especially in the southern Great Plains.

3 ______________________ A boundary between dry upper level winds and moist lower level winds in severe thunderstorms; often site of tornado formation.

4 ______________________ A contact zone between stationary mP air and advancing mT air.

5 ______________________ A blast of cold air that precedes an advancing thunderstorm; caused by evaporation of precipitation in intense downdrafts.

6. ______________________ The rating of both the Barneveld and Oakfield tornadoes.

7. ______________________ Intense swirling of air within the funnel of strong tornadoes; site of the most severe damage

8. ______________________ The type of front that usually is associated with ice storms.

Part III: Short Answer/Diagram.

1. Three methods that Nature uses to cool air to dew point (3 pts.)

a.

b.

c.

2. Diagram a side view (not a top view or a map symbol!) of an occluded front, showing and labeling the associated air masses and cloud types (4 pts.).

3. Diagram a map view of a cold front, using the proper National Weather Service symbol for a cold front and indicating the air masses on either side of the front. Assume that the air mass is located in the US Great Plains (3 pts.).

4. Diagram a side view of a hurricane, showing its structure. Show and label the armbands, the wall cloud, the eye, the ocean surface, and the tropopause (3 pts.).

5. The three characteristics that define a winter storm as a blizzard are (3 pts.)

a.

b.

c.

6. Explain in one paragraph why true blizzards are so dangerous. To do this, relate the characteristics of the blizzard to the meteorological causes of those effects (5 pts.).

7. Define a storm surge and then explain why storm surges are so deadly in places like the Gulf of Mexico and the Bay of Bengal.

a. Definition (2 pts.):

b. Explanation of why so deadly (3 pts.)

Part V. Meteorological Basics (one point each; twenty points total). Please circle the correct answer or fill in the blank.

1. Air along a cold front (rises, falls).

2. High winds are caused by a (gentle, steep) horizontal pressure gradient.

3. Tornadoes are usually associated with a (cold, warm) front.

4. Hurricanes are associated with what air mass? _____

5. The dry adiabatic lapse rate is used when relative humidity is ____________________________

6. On a global scale, air rises at what latitudes? ______________ and ______________

7. A nongeostrophic wind flows when the Coriolis Effect is (equal to, less than, greater than) the horizontal pressure gradient force.

8. Approximately ________% of SWY is absorbed by the earth’s surface.

9. The atmosphere radiates (SWY, LWY, SWX, LWX) radiation. (Note: two answers are required.)

10. If you drove up a mountain, the temperature would (rise, fall) at a rate of _______________________.

11. As the pressure gradient increases, wind speeds (increase, decrease).

12. The day of the year when Manitowoc receives its maximum insolation: ___________________

13. The time of the year when Manitowoc experiences its maximum temperatures. _________________

14. The cause of those maximum high temperatures: _______________________________________

15. Air is at dew point when the relative humidity equals ________________.

16. Along a front, pressure (rises, falls).

17. Along a front, air molecules (rise, fall).

Part IV. Forecast. Using the two maps below and the values in the chart on the next page, make a forecast for Manitowoc for August 6. In the right hand row, explain why you made the forecast that you did. Remember that your explanation is far more important than the values of the parameters. Twenty points.

PARAMETER	AUGUST 5	AUGUST 6	EXPLANATION
Air Mass(es)	mT
Cloud Type	Stratocumulus
Cloud Cover – Percent	15%
Temperature	87°F
Relative Humidity	65%
Precipitation Type, if any: Amount:	None
Pressure	29.7/falling rapidly
Wind Direction	NE
Wind Speed	6-7 mph
Storm Activity	None